Helicopter Wallpapers

Helicopter - photo; Transportstation.org A helicopter is an aircraft which is lifted and propelled by one or more horizontal rotors (propellers). Helicopters are classified as rotary-wing aircraft to distinguish them from conventional fixed-wing aircraft. The word helicopter is derived from the Greek words helix (spiral) and pteron (wing). The engine-driven helicopter was invented by the Slovak inventor Jan Bahyl. The first stable, fully-controllable helicopter placed in production was invented by Igor Sikorsky. Compared to conventional fixed-wing aircraft, helicopters are much more complex, more expensive to buy and operate, relatively slow, have shorter range and restricted payload. The compensating advantage is maneuverability: helicopters can hover in place, reverse, and above all take off and land vertically. Subject only to refuelling facilities and load/altitude limitations, a helicopter can travel to any location, and land anywhere with enough space (a diameter of length 1.5 times the rotor disk). Compared to other vertical lift aircraft like +Tiltrotors (V-22 Osprey for example)and Vectored Thrust airplanes (AV-8 Harrier for example), helicopters are very efficient, carrying more than twice the payload, consuming less fuel in hover and costing considerably less to buy and operate. However these other configurations have considerably more cruise speed than a helicopter (270 Km/Hr for a helicopter, 460 Km/Hr for a tiltrotor, 900+ Km/Hr for a vectored thrust airplane).
History: Since 400 BC the Chinese had a bamboo flying top that was used as a children's toy. This toy eventually made its way to Europe and has been depicted in a 1463 European painting. Pao Phu Tau (抱朴子) was a 4th century book in China that described some of the ideas in a rotary wing aircraft. The first semi-practical idea of a human carrying helicopter was first conceived by Leonardo da Vinci around 1490, but it was not until after the invention of the powered airplane in the 20th century that actual helicopters were produced. Developers such as Jan Bahyl, Oszkár Asboth, Louis Breguet, Paul Cornu,Traian Vuia, Emile Berliner, Ogneslav Kostovic Stepanovic and Igor Sikorsky pioneered this type of aircraft, with Juan de la Cierva introducing the first practical autogiro in 1923 that was to be the basis for the modern helicopter. A flight of the first fully controllable helicopter was demonstrated by Raúl Pateras de Pescara 1916 in Buenos Aires, Argentina. In 1922, Albert Gillis von Baumhauer, a Dutch aeronautical engineer, started studying the possibilities of VTOL rotor craft. His first prototype flew ('hopped' and hovered really) on September 24, 1925, with Dutch Army-Air arm Captain Floris

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